Inhibition of Experimental Lung Inflammation and Bronchitis by Phytoformula Containing Broussonetia papyrifera and Lonicera japonica

Abstract

Broussonetia papyrifera and Lonicera japonica have long been used in the treatment of inflammatory disorders, especially respiratory inflammation, in Chinese medicine. Previously, phytoformula (BL) containing B. papyrifera and L. japonica was found to exert strong anti-inflammatory activity in vitro and in vivo. In this study, the effects of BL on lung inflammation including bronchitis were examined in vitro and in vivo. BL (10-100 <TEX>${\mu}g$</TEX>/ml) inhibited nitric oxide (NO) production of lipopolysaccharide (LPS)-treated alveolar macrophages, MH-S cells, primarily by down-regulating inducible NO synthase. BL also inhibited production of the proinflammatory cytokines, TNF-<TEX>${\alpha}$</TEX> and IL-6. Against an animal model of pleural cavity inflammation, BL (200-400 mg/kg) significantly inhibited 5 h and 24 h carrageenan-induced pleurisy in rats when administered orally. Additionally, BL inhibited experimental bronchitis induced by intratracheal instillation of LPS to rats. Taken together, these results indicate that BL may be effective for the treatment of human lung inflammation as well as bronchitis.